<?php
/**
 * Zend Framework
 * LICENSE
 * This source file is subject to the new BSD license that is bundled
 * with this package in the file LICENSE.txt.
 * It is also available through the world-wide-web at this URL:
 * http://framework.zend.com/license/new-bsd
 * If you did not receive a copy of the license and are unable to
 * obtain it through the world-wide-web, please send an email
 * to license@zend.com so we can send you a copy immediately.
 * @category Zend
 * @package Zend_Filter
 * @copyright Copyright (c) 2005-2012 Zend Technologies USA Inc. (http://www.zend.com)
 * @license http://framework.zend.com/license/new-bsd New BSD License
 * @version $Id: Digits.php 24593 2012-01-05 20:35:02Z matthew $
 */
/**
 *
 * @see Zend_Filter_Interface
 */
require_once 'Zend/Filter/Interface.php';

/**
 *
 * @category Zend
 * @package Zend_Filter
 * @copyright Copyright (c) 2005-2012 Zend Technologies USA Inc. (http://www.zend.com)
 * @license http://framework.zend.com/license/new-bsd New BSD License
 */
class Zend_Filter_Digits implements Zend_Filter_Interface {

    /**
     * Is PCRE is compiled with UTF-8 and Unicode support
     * @var mixed
     *
     */
    protected static $_unicodeEnabled;

    /**
     * Class constructor
     * Checks if PCRE is compiled with UTF-8 and Unicode support
     * @return void
     */
    public function __construct () {
        if (null === self::$_unicodeEnabled) {
            self::$_unicodeEnabled = (@preg_match ('/\pL/u', 'a')) ? true : false;
        }
    }

    /**
     * Defined by Zend_Filter_Interface
     * Returns the string $value, removing all but digit characters
     * @param string $value
     * @return string
     */
    public function filter ($value) {
        if ( ! self::$_unicodeEnabled) {
            // POSIX named classes are not supported, use alternative 0-9 match
            $pattern = '/[^0-9]/';
        } else 
            if (extension_loaded ('mbstring')) {
                // Filter for the value with mbstring
                $pattern = '/[^[:digit:]]/';
            } else {
                // Filter for the value without mbstring
                $pattern = '/[\p{^N}]/';
            }
        return preg_replace ($pattern, '', (string) $value);
    }

}
